Apparatus for drying film



3, 1 68 w. H. OLSON 3,413,730

APPARATUS FOR DRYING FILM Filed May 12, 1967 ted States Patent 3,413,730 APPARATUS FOR DRYING FILM Wilfred H. Olson, 50 Alexandre Tache Blvd., Hull, Quebec, Canada Filed May 12, 1967, Ser. No. 638,005 Claims priority, application Canada, May 16, 1966, 960,481 7 Claims. (Cl. 34--73) ABSTRACT OF THE DISCLOSURE An apparatus is provided for drying wet film-like material such as photographic film, the apparatus being in the form of an enclosed essentially air-tight, dust free chamber containing a temperature controlled heating coil and a moisture trapping means located at the lower portion of the chamber.

This invention relates to the drying of wet material subject to dimensional changing during the drying stages. More particularly, this invention relates to the drying of photographic film.

One of the conventional ways of drying wet film; e.g., photographic film immediately after it has been processed and washed is by passing a stream of hot filtered air around the hanging photographic film which is to be dried. This technique is deficient in that the movement of the air causes the film to move and tends to bring about undesirable dimensional changes. In addition, it is possible for the photographic film to become contaminated. Finally unless the air is quite hot and is moving at excessive speeds, the drying time is considerable, i.e., of the order of minutes.

Another recent proposal involves the absorption of the moisture by the use of an absorbent material, i.e., a silica gel absorbent. This achieving of drying in the absence of added heat makes the drying time approach hours, and consequently is unsuitable.

An object of one aspect of this invention is the provision of means for drying photographic film in a more expeditious manner.

An object of another aspect of this invention is the provision of means for drying photographic film in an essentially dust free environment.

An object of yet another aspect of this invention is the provision of means for drying photographic film evenly in an essentially shrink free condition.

By a broad aspect of this invention, an apparatus is provided for drying wet film-like material (e.g. processed and washed photographic film) subject to easy contamination and dimensional change during such drying, said apparatus comprising (a) an enclosed essentially air-tight, dust free chamber, (b) access means to said chamber, (c) heating means Within said chamber, said heating means including means for providing an essentially constant controlled selected temperature Within said chamber, (d) moisture trapping means at a lower portion of said chamber, and (e) means within said chamber for retaining said film-like material in a generally vertical disposition. Optionally, the enclosed chamber is provided with heat insulation material thereby to assist in maintaining said selected substantially constant temperature.

In a preferred aspect of this invention the heating means (c) is an electrical heater, provided with a thermostat to maintain the temperature at a selected substantially constant value. In an especially preferred aspect of the invention, the heater is disposed near the bottom of the chamber, but the thermostat is disposed near the top of the chamber. In another especially preferred aspect of this invention, the temperature is between 100 F. and 150 F.

By another aspect of this invention the moisture trapping means (d) is a coil condenser in which is circulating a cool fluid, preferably cold water. Convention diliquescent material, i.e., silica gel, calcium chloride, etc. may also be used.

By yet another aspect of this invention the means (e) are hangers upon which the film is hung and clips at the bottom of the film to hold the film in essentially vertical position by means of gravity.

A practical optional feature is the provision of a light fixture to light the interior of the chamber.

The accompanying drawing is an isometric view of the apparatus according to one embodiment of this invention.

The invention, in this embodiment simply consists of an air-tight, dust-excluding insulated enclosure box 10 provided with an insulated door 11, swinging on hangers 12 and including a handle 13 to maintain the air-tight dustexcluding environment Within the box 10 when the door 11 is closed.

Disposed at the lower portion of the box 10 is an electrical heater 14 connected by Wires 15 to a temperature control 16 of a thermostat 17, both mounted on the rear Wall of the box 10. By these means, it is possible to adjust the temperature control 16 to any desired temperature, usually between F. and F. and the thermostat 17 maintains essentially that temperature by suitable conventional on-off control of the electric heater. Other heaters, such as infra-red, radiant, etc., heaters may be used.

Also disposed at the bottom of the box 10 is a waterfilled condenser 18 provided with a water inlet 19, a control coil portion 20 and a water outlet 21. As shown in the embodiment, the coil is disposed above, but adjacent to, the heater 14.

Disposed at the top of the box 10 is a plurality of hangers 22, depending from which are a plurality of wet photographic films 23. Clipped to each film at the lower ends thereof are clips to maintain the films disposed in essentially vertical position by gravity.

In operation, the wet photographic film 23 is hung by the hangers 22. The temperature control 16 is adjusted to the desired temperature and the door 11 is closed. As the temperature within the box 11 increases, the water is driven ofl the film and the dust free air within the box 10 becomes more humid. As the air contacts the cool coils 18, the water in the air condenses out, thereby permitting the air to absorb more Water driven off the film. Drying takes place in about 5 to 8 minutes time, depending on the quantity of film to be dried.

After use, the box 10 is permitted to become less humid by leaving the door open.

I claim:

1. Apparatus for drying wet film-like material subject to easy contamination and dimensional change during such drying, said apparatus comprising:

(a) an enclosed essentially air-tight, dust free chamber;

(b) access means to said chamber;

(c) heating means within said chamber, said heating means including means for providing an essentially constant controlled selected temperature within said chamber;

(d) moisture trapping means at a lower portion of said chamber; and

(e) means within said chamber for retaining said filmlike material in a generally vertical disposition.

2. The apparatus of claim 1 wherein said heating means (c) is an electric heater.

3. The apparatus of claim 2 wherein the moisture trapping means (d) comprises a hollow metallic coil including inlet means for cooling fluid circulating therein and outlet means therefrom.

4. The apparatus of claim 3, wherein said cooling fluid is cold water.

5. The apparatus of claim 1 wherein the moisture trapping means (d) comprises a hollow metallic coil including inlet means for cooling fluid circulating therein and outlet means therefrom.

6. The apparatus of claim 3 wherein said cooling fluid is cold water.

7. The apparatus of claim 1 wherein said film-like material retaining means (e) are film clips secured near the upper portion of said chamber.

4 References Cited UNITED STATES PATENTS 1,679,239 7/ 1928 Cassereau 34-163 XR 3,138,437 6/1964 Buck 34-163 3,286,370 11/1966 Hope 34163 KENNETH W. SPRAGUE, Primary Examiner. 

